Intaglio printing processes such as gravure printing have hitherto been used to form conductor patterns such as electromagnetic shielding patterns in electromagnetic shielding materials for use in, e.g., plasma display panels (PDP) (see, for example, Patent Documents 1 to 8). One such example, the transparent base material with electromagnetic shielding film described in Patent Document 1, is manufactured by forming an underlayer over the entire top side of a transparent base material; using a gravure printing process to form on the underlayer a catalyst ink layer in a predetermined pattern; then using a plating process to form on the catalyst ink layer a metal layer of the same pattern shape as the catalyst ink layer.
Here, the underlayer is formed using a material containing, for example, oxide fine particles and an organic polymer; a porous structure is thought to form on account of the presence of the oxide fine particles. The catalyst ink layer is formed using a catalyst ink containing, for example, noble metal fine particle-supporting oxide fine particles, an organic polymer and an organic solvent. When the catalyst ink layer is formed on the underlayer by a gravure printing process, as shown in FIG. 13, first, the organic solvent within the catalyst ink 23 that has been filled into the pattern grooves 22 on the plate cylinder 21 is absorbed into the porous underlayer 24, as a result of which the viscosity of the catalyst ink 23 rises. Apparently, the catalyst ink 23 which has hardened to an appropriate degree grips the porous underlayer 24, enhancing adherence between the catalyst ink 23 and the underlayer 24 by an anchoring effect, and the catalyst ink 23 is pulled from the pattern grooves 22 on the plate cylinder 21. In FIG. 13, “12” represents a doctor for scraping off excess catalyst ink 23, “25” is a transparent base material, and the arrows indicate the direction of flow by the organic solvent.